The present invention is directed to storage racks and more particularly to a storage rack for holding a plurality of substantially box-like storage containers one above the other capable of being used in a cryogenic environment.
In medical, research and biological laboratories it is often necessary to store biological or other type samples at ultra low temperatures, temperatures below -20.degree. Centigrade, or in a cryogenic environment, i.e., temperatures below -100.degree. Centigrade. Typically Biological samples are placed in a cryogenic vial, a plurality of which are placed in a storage container. A plurality of storage containers are then placed in a rack which is placed in a mechanical freezer or vessel containing a cryogenic medium such as liquid nitrogen vessel containing liquid nitrogen preferably have a working temperature at the opening at -150.degree. Centigrade or below in order to assure the viability of frozen cells for long periods of time. Quite often it is necessary to retrieve only vials from a single storage box from the plurality of storage boxes placed in the rack. In order to protect the viability of the samples not used it is important to return the rack to the cryogenic environment as quickly as possible. While it may not appear that a sample removed from a cryogenic environment and held briefly at an ambient temperature has warmed, every time a sample has been brought to warmer environments even briefly, it experiences a change in temperature. Thus when removing a sample from cold storage, care should be taken to avoid exposure of other samples to the warmer temperature. Repeated warming and recooling of stored samples will reduce the viable storage time. Certain samples are extremely sensitive to temperature change, even of short duration. In the prior art, a long rod is used to keep all of the storage containers within the rack. When the rack is removed from the cryogenic environment the rod is pulled out allowing access to all of the storage containers. However, if the rack is inadvertently tipped or jarred there is high risk that a storage container will fall from the rack thereby potentially damaging the samples.
Applicants have invented an improved rack for holding a plurality of storage containers having means for independently locking and maintaining each of the containers within the rack which allows quick and easy access thereto.